反应机理对air/H_2燃烧系统多场耦合仿真的适用性

Applicability of reaction mechanisms to multi-field coupling simulation of air/H_2 combustion system

针对某air/H_2燃烧系统,建立起流动、传热、燃烧多场耦合有限体积动态数值模型,构建了通用化的反应机理库和配套的物性参数库,分别采用热力计算方法和3套氢氧反应机理方法进行仿真;基于反应机理的仿真描述了点火与熄火过程,揭示了各基元反应和组分变化对燃烧流动瞬态过程的影响。与已经过试验验证的热力计算方法对比,结果表明:Williams机理符合最好,Conaire机理次之,Evans机理符合相对较差。相比Conaire机理,采用Williams反应机理使反应熄火温度由1200K降低至1155.3K,在1222.3K的低温工况下,计算结果误差由Conaire机理的4.7%降低至2.74%,使多场耦合数值系统的应用范围更广、计算结果更佳;低温工况下,H_2O_2及其相关反应对氢氧机理的描述精度会产生较大影响。

For an air-hydrogen combustion system,a dynamic finite volume numerical model considering the multi-field coupling of flow,heat transfer and combustion was established,ageneral library of reaction mechanisms and physical property parameters was constructed.The thermodynamic calculation method and three sets of hydrogen-oxygen reaction mechanism methods were used for simulation calculation,and the latter can also describe the process of ignition and flameout,and reveal the impact of various elementary reactions and species changes on the combustion and flow transient process.The Williams mechanism fitted best with the results of the thermodynamic calculation,which was validated by experiments,followed by the Conaire mechanism,and the Evans mechanism was relatively poor.Compared with the Conaire mechanism,Williams reaction mechanism lowered the quenching temperature from 1 200 Kto 1 155.3 K,reduced the calculation error from 4.7% to 2.74%under the low temperature condition of 1222.3 K,and made the application of multi-coupling numerical system more extensive and the calculation result better.Under low temperature,H2O2 and related reactions had a great influence on the description accuracy of the hydrogenoxygen mechanism.